doc:Remove transparency from headers scheme picture background

doc/headers.svg

@@ -27,9 +27,9 @@
      inkscape:deskcolor="#d1d1d1"
      inkscape:document-units="mm"
      showgrid="false"
-     inkscape:zoom="1.3719136"
-     inkscape:cx="500.39594"
-     inkscape:cy="231.06411"
+     inkscape:zoom="0.97008941"
+     inkscape:cx="558.19597"
+     inkscape:cy="363.88398"
      inkscape:window-width="1920"
      inkscape:window-height="979"
      inkscape:window-x="0"
@@ -257,6 +257,16 @@
      inkscape:label="Layer 1"
      inkscape:groupmode="layer"
      id="layer1">
+    <rect
+       style="fill:#ffffff;fill-opacity:1;stroke:#000000;stroke-width:0.161779;stroke-linecap:round;stroke-linejoin:round;stroke-dasharray:none;stroke-opacity:1"
+       id="rect13521-3"
+       width="161.4944"
+       height="68.120209"
+       x="27.111593"
+       y="30.975336"
+       inkscape:export-filename="headers.png"
+       inkscape:export-xdpi="200"
+       inkscape:export-ydpi="200" />
     <rect
        style="fill:#8fff7c;fill-opacity:1;stroke:none;stroke-width:0.0566048;stroke-linecap:round;stroke-linejoin:round;stroke-dasharray:none"
        id="rect5714"
@@ -1097,13 +1107,6 @@
          style="font-style:normal;font-variant:normal;font-weight:600;font-stretch:normal;font-family:FreeSans;-inkscape-font-specification:'FreeSans Semi-Bold';fill:#0000ff;fill-opacity:1;stroke-width:0.0705427"
          x="169.36992"
          y="57.440353">Data I/O</tspan></text>
-    <rect
-       style="fill:#0000ff;fill-opacity:0;stroke:#949494;stroke-width:0.332414;stroke-linecap:round;stroke-linejoin:round;stroke-dasharray:none;stroke-opacity:1"
-       id="rect2932"
-       width="170.6443"
-       height="71.961319"
-       x="23.69591"
-       y="28.181168" />
     <text
        xml:space="preserve"
        style="font-size:1.65698px;line-height:1.25;font-family:FreeSans;-inkscape-font-specification:FreeSans;letter-spacing:0px;word-spacing:0px;fill:#000000;fill-opacity:1;stroke-width:0.06904"